strlen() and passing by address

Is the strlen function used this way?

Code:

---

Insert(char *s, int index)
{
  int size_of_string = Size();
  int length = strlen(s);
  int sum = size_of_string + sum;
}

---

If not what would be the alternative?

strlen takes the length of a char* string. I don't know what you're trying to do with your code. char* strings are passed by pointer when they're given as arguments. (No extra copy is made, so any modifications made to that string are still there when that function exits.)

Info about strlen e.i. arguments and return values.

Code:

---

Insert(char *s, int index)
{
  int size_of_string = Size();
  int length = strlen(s);
  int sum = size_of_string + sum;//This line is dangerous because sum is uninitialized
}

---

Try and print the variable sum. Not as expected? Why? Variable sum contains a garbage value. If this was a pointer variable you would have a serious BUG.
Solution: Always initialize a variable when it is possible!